1. Field of the Invention
The present invention is addressed to an exciter circuit used as part of an engine ignition system, and in particular, an exciter circuit controlled by a full authority digital engine control, or FADEC.
2. Description of the Prior Art
Conventional ignition systems are well known in the art and typically include an exciter circuit having an energy storage device such as a capacitor and a circuit for charging the capacitor. The system will also include one or more igniter plugs in the circuit and a switching mechanism as part of a discharge circuit connected between the capacitor and the igniter. In aerospace applications, the switching mechanism has commonly been a spark gap, although more recently, solid state switching systems utilizing semiconductors have been employed in place of the older spark gap switching.
Because of the numerous electronic inputs and controls that must be exercised over a modern gas turbine engine, a system known as a Full Authority Digital Engine Control, or "FADEC", has evolved to assist an aircraft pilot in managing these various inputs and controls. The FADEC is essentially a multiple channel computer that receives a limited number of information inputs from the aircraft pilot, as well as continuous input from the various sensors, switches, and drivers that are placed throughout the engine system. The FADEC analyzes the various inputs from these devices and sends control signals back to these devices to manage their operation. The FADEC system is known in the art, and was first disclosed in U.S. Pat. No. 4,718,229 to Riley issued on Jan. 12, 1988.